Dithiophosphonic acid esters



United States Patent F 3,361,855 DITHIOPHOSPHONIC ACID ESTERS Gerhard Schrader, Wuppertal-Cronenberg, Germany, assignor to Farbenfabriken Bayer Aktiengesellschaft,

Leverkusen, Germany, a corporation of Germany No Drawing. Filed Feb. 9, 1961, Ser. No. 88,026 Claims priority, application Germany, Feb. 13, 1960, F 30,537 Claims. (Cl. 260956) In the above formula, R denotes an arbitrary aliphatic residue, R, a lower alkyl residue, and R an, optionally substituted, aryl and particularly phenyl residue, or a higher alkyl or cycloalkyl residue with 6 or more C- atoms.

It has been found that these aliphatic dithiophosphonic acid-O-alkyl-S-aryl or -cycloalkyl or -higher alkyl esters are distinguished by good insecticidal activity. Such compounds are particularly effective against pests which already exhibit signs of resistance towards the corresponding dithiophosphoric acid esters which are known, in part, from German patent specification 1,026,323.

Within the scope of this application, the term aliphatic residues refers to saturated as Well as unsaturated residues which may optionally also be further substituted, e.g. by halogen atoms, aryl residues (particularly phenyl residues), and the like. The term cycloalkyl or higher aliphatic alkyl esters is intended to refer to compounds wherein the cycloalkylor higher alkyl-residues contain 6 or more C-atoms.

The preparation of the compounds obtainable according to the invention is effected by ways and means whose principle is known i.e., e.g., by reaction of the corresponding thionophosphonic acid-O-alkyl ester halides with corresponding mercaptans, as it may be seen from the following equation:

Hal SRa In this equation the symbols have the same significance as said above.

The above-mentioned reaction is preferably carried out in inert solvents, e.g. alcohol, acetone, benzene, toluene, and sometimes even in water, whereupon the reaction products according to the invention are usually obtained with good yield and purity.

The new compounds of the present invention very eflfectively kill insects like flies, mites, aphids, etc. They distinguish themselves especially by a good contact-insecticidal activity and at the same time by an activity on eating insects such as caterpillars. The compounds may be used in the same manner as other known phosphoric acid insecticides, i.e. in a concentration from about 0.00001% to about 1%, diluted or extended with suitable solid or liquid carriers or diluents. Examples of such solid carriers are talc, chalk, bentonite, clay and the like, as liquid carriers there may be mentioned water (if necessary with commercial emulsifiers), alcohols, especially lower alcohols such as methanol or ethanol, ketones, especially lower ketones such as acetone or methyl ethyl ketone, liquid hydrocarbons and the like. The new com- 3,361,855 Patented Jan. 2, 1968 pounds may furthermore be used in combination with each other or with known insecticides, fertilizers etc.

As an example for the special utility of the inventive compounds the esters of the following formulae:

have been tested against (I) spider mites and aphids and (II) against spider mites and mosquito larvae. Aqueous solutions of the aforementioned compound have been prepared by admixing them with the same amount of an auxiliary solvent (acetone). A commercial emulsifier (benzyl hydroxy diphenyl polyglycol ether) is added in an amount of 20% referred to active ingredient. This premixture then is diluted with water to the desired concentration. The tests have been carried out as follows:

(a) Against spider mites (contact insecticidal action with compound 1). Bean plants (Phaseolus vulgaris) of about 15 inches height are sprayed drip wet with solutions as prepared above in a concentration as shown below. The bean plants have been infested heavily with the two-spotted spider (species T etranychus telarius). Evaluation has been carried out after 24 hours, 48 hours and 8 days. The results may be seen from the table below.

(b) Against spider mites (ovicidal action with compound II). Bush beans (Phaseolus vulgar-is) infested with about 100 eggs of Tetranychus lelarz'us Hanst (two-spotted spider) are sprayed drip Wet with aqueous emulsions as prepared above. Evaluation occurs after 8 days. Each experiment has been rechecked after 14 days. The results may be seen from the table below.

Percent I and II 0.001 Killing rate 100 (c) Against aphids (species Doralis fabae). Heavily infested bean plants (Vizia faba) have been sprayed drip Wet with solutions as prepared above in a concentration as shown below. The efiect has been determined by evaluation after 24 hours by counting the dead pests either on the surface of the soil or still remaining on the plants.

The following results have been obtained:

Aphids were 40% killed with 0.001% solutions. (d) Against mosquito larvae of the type Aedes aegypt: about 20 larvae were brought into diluted aqueous emulsions prepared as described above. Counting of the dead pests occurred after 24 hours. The following results have been obtained: Mosquito larvae are killed with 0.000001% solutions.

The following examples are given for the purpose of illustrating the process according to the invention.

EXAMPLE 1 28 g. (0.25 mol) of thiophenol are dissolved in 50 ml. of methanol. To this is added a solution of sodium methoxide which contains 0.25 mol of dissolved sodium. It is warmed to 60 C. for a short while, and is then cooled to 30 C. 37 g. of methyl-thionophosphonic acid-O-methyl ester-chloride (B.P. 50 C./ 12 mm. Hg) are then added dropwise at 30 C., and it is stirred at 30 C. for another hour. Thereafter, the reaction product is added to 300 ml. of ice water, and the separated oil is taken up in 300 ml. of benzene. The benzene solution is thoroughly washed with water and dried with sodium sulphate. On fractionation, there are obtained 32 g. of the novel methyl-thionophosphonic acid-O-methyl-S-phenyl ester of B.P. 92 C./ 0.01 mm. Hg. Yield 59% of the theoretical. LDQ on rats per es 100 mg./kg.

Flies are completely killed with 0.001% solutions. Aphids are 100% killed with solutions of 0.01%.

EXAMPLE 2 S OCH:

37 g. (0.25 mol) of p-chloro-thiophenol are dissolved in 50 ml. of methanol. Thereafter, a solution of sodium methoxide is added which contains 0.25 mol of dissolved sodium. Then, 37 g. of methyl-thionophosphonic acid-O methyl ester-chloride are added dropwise at 30 C. It is maintained at 3035 C. for another hour, and is then worked up by the usual method. Thus, there are obtained 25 g. of methyl-thionophosphonic acid-O-methyl-S-p-chlorophenyl ester of B.P. 106 C./ 0.01 mm. Hg. Yield 40% of theory. LD on rats per os 25 mg./kg.

Flies are completely killed with 0.001% solutionsCaterpillars are 100% killed with solutions of 0.1%.

The following compounds can be obtained by a similar method:

S OCH:

CHr-P Yield 76%, DL 175 mg./kg. Flies are completely killed with 0.001% solutions. Systemic action with 0.1% solutions is 100%.

H CHr-P Yield 36%. B.P. 98 C./0.'01 mm. Hg DL 100 mg./ kg.

Mosquito larvae are completely killed with 0.0001% solutions. Caterpillars are completely killed with 0.1% solutions.

Yield'69%. B.P. 93 C./0.01 mm. Hg DL 5 rug/kg. Aphids are completely killed. with 0.01% solutions. Flies are 80% killed with 0.0001% solutions.

8 OCzHs Il/ OH -P i Yield 44%. B.P. 104 C./0.01 mm. Hg DL 10 mg./ kg.

IS OCa s s OOH; ll/

28 g. (0.25 mol) of thiophenol are dissolved in 50 ml. of methanol. Thereafter, there is added a solution of sodium methoxide which contains 0.25 mol of dissolved sodium. 40 g. of ethyl thionophosphonic acid-O-methyl' ca si 37 g. (0.25 mol) of p-chloro-thiophenol are dissolved in 50 ml. of methanol. A solution of sodium methoxide containing 0.25 mol of dissolved sodium is added to the solution. 40 g. of ethyl-thionophosphonic acid-O-methyl ester-chloride are added dropwise at 35 C. whilst stirring well. It is maintained at 40 C. for another hour, and is then worked up by the usual method. Thus', there are obtained 48 g. of .ethyl-thionophosphonic acid-O- methyl-S-p-chlorophenyl ester as colorless needles.'M.P.

76 C. Yield 72% of the theoretical.

Flies are completely killed with 0.0001% solutions. Mosquito larvae are killed with 0.000001% solutions. r

EXAMPLE 5 S OCH:

31 g. (0.25 mol) of p-methyl-thiophenol are dissolved in 50 ml. of methanol. A solution of sodium methoxide containing 0.25 mol of dissolved sodium is added to it. Thereafter, 40 g. of ethyl-thionophosphonic acid-O- methyl ester-chloride (B.P. 44 C./1 mm. Hg) are allowed,

to run in at 30 C. It is maintained at 30 C. for another hour, and is then Worked up as in Example 1. By this method, 46 g. of ethyl-thionophosphonic acid-O-m'ethyl- S-p-methylphenyl ester of B.P. 103 C./0.01 mm. Hg are obtained. Yield 75 of the theoretical. LD on rats per os mg./ kg.

Caterpillars are completely method:

Yield 73%. B.P. 92 C./0.01 mm. Hg LD 10 mg./l g.

Spider mites are completely killed with 0.001% solutions, .Aphids are 40% killed with solutions of 0.001%.

0 Cal-Is Yield 81%. B.P. 1 02" 0.70.01 mm. Hg Ln 1o mg./kg.'

killed with 0.1% solutions. Mosquito larvae are 100% killed with 0.0001% solutions The following compounds can be obtained by a similar eggs of the red spider. Mosquito larvae are 90% killed with 0.000001% solutions.

8 OCaHs OCH:

37 g. (0.25 mol) of p-chlorophenyl-mercaptan are dissolved in 50 ml. of methanol. A solution of sodium methoxide containing 0.25 mol of dissolved sodium is added to it with stirring. 45 g. of a-chloromethyl-thiophosphonic acid-O-methyl ester-chloride (B.P 52 C./1 mm. Hg) are thereafter added at 30 C. with more stirring. It is stirred for one hour, and the reaction product is then added to 300 ml. of water. The separated oil is taken up in 200 ml. of benzene. The benzene solution is washed with water until neutral, and thereafter dried with sodium sulphate. When the solvent is distilled off, 40 g. of the novel ester are obtained as a pale yellow oil, insoluble in water. Yield 56% of the theoretical.

Calculated for mol weight 287: C], 24.7%; S, 22.3%; P, 10.8%, Found: Cl, 24.4%; S, 23.3%; P, 10.4%.

LD on rats per 03 1000 mg./ kg. Caterpillars are completely killed with 0.1 solutions.

There are obtained by a similar method:

S OCH;

Il/ (ll-CHr-P Aphids are completely killed with 0.01% solutions. Caterpillars are 100% killed with 0.1% solutions.

Yield 63 LD 100 mg./kg.

EXAMPLE 7 28 g. (0.25 mol) of thiophenol are dissolved in 100 ml. of anhydrous ethyl alcohol. A solution of sodium ethoxide containing 0.25 mol of dissolved sodium is added to it. 57 g. of cyclohexyl-thionophosphonic acid-O-ethyl esterchloride (B.P. 63 C./0.01 mm. Hg) are thereafter added at 35 C. for another hour, and the reaction product is then added to 400 ml. of water. The separated oil is taken up in 300 ml. of benzene, and worked up by the usual method. In this way, 56 g. of the novel ester are obtained as a pale yellow oil insoluble in water. Yield 75% of the theoretical.

Calculated for mol weight 300: S, 21.3%; P, 10.3%. Found: S, 21.3%; P, 9.6%.

LD on rats per os 1000 mg./kg. Flies are completely killed with 0.1% solution.

6 The following compound is obtained by a similar method:

Yield 69%. 1000 mg./kg. without symptons.

EXAMPLE 8 O CzHs 39 g. (0.25 mol) of p-chloro-thiophenol are dissolved in 120 ml. of anhydrous ethyl alcohol. A solution of sodium ethoxide containing 0.25 mol of dissolved sodium is added at 30 C. 51 g. of isobutenyl-thiophosphonic acid-O-ethyl ester-chloride (B.P. 50 C./0.01 mm. Hg) are thereafter added dropwise at 30 C. whilst stirring Well. It is maintained at 30 C. for an hour, and the reaction product is then added to 300 ml. of ice water. The separated oil is taken up in 300 ml. of benzene, washed with water until neutral, and worked up by the usual method. There are obtained 59 g. of the novel ester as a pale yellow oil insoluble in water. Yield 77% of the theoretical. LD on rats per os 500 mg./ kg.

Calculated for mol weight 307: CI, 11.6%; S, 20.9%; P, 10.1%. Found: Cl, 12.4%; S, 21.5%; P, 10.1%.

Spider mites are 80% killed with 0.001% solutions. The compound shows an ovicidal action against the eggs of the red spider.

The following compounds can be prepared by a similar method:

Yield 80%. B.P. 99 C./0.01 mm. Hg LD 500 mg./ kg.

Mosquito larvae are completely killed with 0.001% solutions.

IS OCzHs Yield 78%. LD 1000 mg./ kg.

S OCzHs SCuHra Yield 87%. B.P. 87 C./0.01 mm. Hg LD 1000 mg./kg.

EXAMPLE 9 30 g. (0.25 mol) of n-hexyl-mercaptan are dissolved in ml. of anhydrous ethyl alcohol. A solution of sodium ethoxide containing 0.25 mol of dissolved sodium are added dropwise at 30 C. 64 g. of styryl-thionophosphonic acid-O-ethyl ester-chloride (B.P. 97 C./0.01 mm. Hg) are then added at 30 C. It is stirred for another hour, and is then worked up by the usual method. Thus, 65 g.

of the novel ester are obtained with B.P. 134 C./0.01

mm. Hg. Yield 79% of the theoretical. LD on rats per es 500 mg./kg.

There can be obtained by the same method:

Yield 90%. L13 50 mg./kg.

- Yield 65%. LD 1000 mg./kg.

S 02 5 ll CH=CHP Yield 77%. LD 1000 mg./kg.

S OCzHs Yield 82%. Ln 500 tug/kg.

EXAMPLE (011930 S OGz s u/ C-I (ohms Yield 75%. LD 1000 mg./kg.

\ ll/ C-P Yield 78%. B.P. 110 C./0.01 mm. Hg LD 500 mg./ kg.

Yield 75%. Yellow oil.

I claim:

1. A compound of the formula:

in which R is methyl, ethyl, chloro-alkyl having up to712 carbon atoms, phenylalkyl having up to 12 carbon atoms or cyclo-hexyl; R is lower alkyl having up to 4 carbon atoms; and R is chlorophenyl.

2. A compound of the formula wherein R is alkyl having up to 12 car-hon atoms, R is lower alkyl having up to 4 carbon atoms, and R is chlorophenyl.

3. A compound of the formula wherein R is methyl or ethyl, R is lower alkyl having up to 4 carbon atoms, and R is chlorophenyl. 4. The compound of the formula:

'28 g. (0.25 mol) 'of phenyl-mercaptan are dissolved in 100 ml. of anhydrous ethyl alcohol. A solution of sodium ethoxide containing 0.25 mol of dissolved sodium are added to it. 65 g. of isooctenyl-thionophosphonic acid-O- ethyl ester-chloride (B.P. 70 C./ 0.01 mm. Hg) are then added dropwise with stirring at 30 C. It is maintained at 30 C. for another hour, and is then worked up by the usual method. Thus, 66 g. of the novel ester are obtained as a pale yellow oil insoluble in water. Yield 82% of the theoretical.

Calculated for mol weight 328: S, 19.5%; P, 9.47%.

Found: S, 18.5%; P, 9.5%.

LD on rats per es 500 mgjkg.

The following compounds can be obtained by a similar method:

Yield 92%. LD 5,00 mg./kg.

(CH3)3C 8 002115 (CHeDaC Yield 78%. B.P. 120 010.01 mm. Hg 1.13 500 mg./ kg.

(CHaOzC 5. The compound of the formula:

6. A compound of the formula S ORi wherein R is R is lower alkyl having up to 4 carbon atoms, and R is chlorophenyl. 7. The compound of the formula:

8. A compound having the formula S 0-3. II/

Where R is lower alkyl.

9. As a composition of matter: O-methyl-S-phenylethylphosphonodithioate.

10. As a composition of matter: O-ethyl-S-phenylmethylphosphonodithioate.

References Cited UNITED STATES PATENTS 2,910,402 10/1959 Fairchild 260461.110 2,967,884 1/1961 Dunn et al 260461.110 2,988,474 6/1961 Szabo et a1. 260461.110 3,029,270 4/1962 Schrader 260--461.110

10 OTHER REFERENCES (I) Kabachnik et :11, Bull Akad Sci U.S.S.R. (Eng. Translation) 185-189 (February 1956).

(II) Kabachnik et al., J. Gen. Chem. U.S.S.R. 26, 5 24912496 (1956).

(HI) Kabachnik et 111., Chemical Abstracts 50, 13727F- 13728a (1956).

(IV) Kabachnik et 211., Chemical Abstracts 50, 11240 10 (1956).

CHARLES B. PARKER, Primary Examiner.

A. H. WINKELSTEIN, M. LIEBMAN, L. U. MARCUS,

Examiners.

D. D. HORWITZ, F. M. SIKORA, I. P. BRUST, R. L.

RAYMOND, Assistant Examiners. 

1. A COMPOUND OF THE FORMULA: 